Psoriatic arthritis (PsA) and rheumatoid arthritis (RA) are chronic inflammatory diseases occurring in patients with autoimmune disorders and psoriasis. A combination of mechanical stress and inflammation in individuals with PsA results in the formation of periosteal bone growth (osteophytes or enthesophytes) at tendon/ligament insertion sites, and articular erosions within the joints. Erosion formation typically occurs in early disease at the proximal enthesis, but in later stages, spur formation occurs at the distal end of the ligament attachment site. The frequency and size of the abnormalities and the number of affected joints are associated with poor clinical outcomes. Some individuals exhibit extremely destructive and disfiguring forms of the disease with erosions and periosteal bone formation leading to disability. The metacarpophalangeal joints of the hand are common areas for these bone changes. Because these changes are irreversible, earlier detection and prevention may lead to improved patient care.
Accordingly, there is a need for a reliable imaging method to detect joint erosion or deformity.